Spinal nerves

This posting about spinal nerve is not covered under spm syllabus. But i hope the diagrams below can give you some understanding about spinal nerve.

We hv 31 pairs of spinal nerves.


1 is spinal cord; 2 is ventral root; 3 is dorsal root; 4 is spinal nerve

Functional types of neurons in spinal nerves (& other nerves):

1. somatic afferent - sensory from general cutaneous receptors (in the skin) & proprioceptors (in skeletal muscles, tendons, & joints)
2. somatic efferent - motor to skeletal muscles
3. visceral afferent - sensory from receptors in the viscera (smooth muscle, cardiac muscle, & glands)
4. visceral efferent - motor to smooth muscle, cardiac muscle, & glands
   
   *viscera =internal organs; singular (viscus)